The simulation and visualization of meteorlogical conditions, ground cloud diffusion and environmental conditions related to flight training is disclosed in the following U.S. Pat. Nos.
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The drift and dispersion of contaminated ground clouds create hazardous and adverse environmental effects as they travel across the earth's surface. Such ground clouds include space shuttle exhaust clouds, nuclear power plant accident, radioactive clouds, plumes from smokestacks and any other type of cloud produced from a pollution source.
Many situations arise where the drift and dispersion of such ground clouds must be monitored in real-time. Such drift and dispersion depend strongly upon prevailing atmospheric conditions at the particular location of the earth surface terrain site. Any system for predicting such cloud drift and dispersion must be capable of operating effectively where the terrain is irregular and complex. Such a system must also take into account the differing wind speeds and direction as it passes over such complex terrain.
As an example, where the launch site of a flight vehicle is over complex terrain, the approaching wind will be irregular with fingers of high speed flow and zones of stagnant or recirculation air occurring simultaneously. The characteristics of such wind flow will depend upon whether it is a nighttime wind or a daytime wind and the particular season of the year in which the ground cloud occurs.
Current techniques for forecasting hazardous cloud drift and dispersion are based on numerical models. Such technique are presently incapable of modeling the effects of complex terrain on cloud transport and diffusion. Thus, numerical models provide poor and unreliable predictions of such cloud drift and dispersion.
In a known comprehensive cloud monitoring program based on numerical modeling of the direction of cloud travel over a terrain site, the REED computer code is used to predict the transport direction of the exhaust ground cloud produced by a flight vehicle launch. During such a launch, the prediction model is run at various times just preceding the launch. Thus, it may begin at 48 hours before the launch and then at specific hours such as 24, 12, 6, 3, and at the time of the launch. However, the REED model is severely lacking in its ability to incorporate topographical effects upon the drift and dispersion of the exhaust cloud of the flight vehicle.
The topography of a launch site is recognized as a major factor controlling the localized weather conditions also referred to as site-specific climate and micrometeorology. Thus, a complicated system of mountains, valleys, points and planes results in a wide variation in local climatic conditions. For instance, fogs are often limited to the immediate area of a shoreline by coastal mountains and proceed inland only along the valleys between the mountains. Higher inland mountains cause strong uplifting of marine air masses leading to cloudiness and rain showers. Where strong temperature inversions occur, they have a significant influence on exhaust cloud drift and dispersion. Such inversions effectively form a lid for the lower atmosphere thereby trapping the exhaust cloud and hindering normal diffusion and dispersion.
Varying terrain or topography plays a particularly important role in the characteristics of any temperature inversion. Furthermore, wind speed and direction may vary greatly as a result of widely varying terrain. There is a necessity for predicting such terrain effects and for predetermining any effect of the variation of wind speed and direction upon the drift and dispersion of such ground clouds.